For example, when I say I "believe in love" am I saying I believe something called "love" exists or am I believing while surrounded by love? If something is considered "out" is it physically away from you or not under consideration?
What is in and what is out may very well be the primary decision process of most of human thought as we continually choose which objects and ideas receive and hold our attention. Attention then becomes thoughts, which become actions that become our life. Much of this process takes place subconsciously in the routines, habits, preferences, and prejudices of our lives. We choose one thing/person or another without realizing we are choosing. We also make conscious choices, but my guess is that even most of our conscious choices are somewhat predetermined by subconscious ones.
Another tendency of this process is that whatever is "in" probably provides comfort and love, and the "out" stuff generates suspicion and fear. This does not necessarily mean that one or the other is good or bad. We can embrace bad things and be fearful of good things.
My point in all of this is to heighten awareness of what/who is "in" and what/who is "out" in our lives, and to realize that we make choices every moment of everyday whether we realize it or not. Our "ins and outs," whether conscious or not, determine our lives